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Full text of "The manufacture and properties of iron and steel"

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METHODS  OF MANUFACTURE.                             233
furnace, must he heated, ored, treated like any other charge and will take half the time that -would be given to an ordinary heat if allowance is made for the interval of making bottom and other delays, which will be a constant for any charge. We have then practically all the increment of the Bessemer except the recar-burizer, and all the increment of the open hearth, including the recarburizer; we have the total working costs of the Bessemer except the molds,,-and at least half the working costs of the open hearth. The sum of these items will exceed the cost of making steel by either the Bessemer converter alone or the open hearth alone. Notwithstanding these arguments, there are places where this combined process is advisable. Thus in Alabama the ores and coke are both inferior, and it is difficult to make iron suitable for a basic open hearth in both silicon and sulphur. The duplex process answers this difficulty by permitting the blast furnace to run at a 'higher temperature and eliminate the sulphur without such stringent specifications concerning sulphur.